Patent GB-191104617-A (GB)
Title: Improvements in and relating to Fluid Pressure Brakes.
Inventor: TURNER WALTER VICTOR
IPC: B60T15/42
Filed: 1911-02-23
Granted: 1911-07-06
Abstract: 4617. Turner, W. V. March 14, 1910, [Convention date]. Fluid-pressure.-A triple valve, adapted for railway fluid-pressure brake apparatus of the kind having duplicate sets of auxiliary reservoirs and brake cylinders of which one set is used for service applications and both sets for emergency applications, is further provided with an application chamber the pressure in which controls the supply of fluid from the service auxiliary reservoir to the service brake cylinder, and with means for ensuring that the valve moves to emergency position only when an emergency application is desired. The application chamber is moreover arranged to be temporarily connected to a reduction chamber during an initial application of the brakes, in order to obtain a pressure in the brake cylinder more nearly equal to that obtained in cars using the ordinary standard brake apparatus. The valve is also such as to provide a graduated release of the brakes. The valve device is shown diagrammatically in Figs. 2 to 4 and comprises a main valve 10 and auxiliary valve 11 operated by a piston 4, which is subjected at one side to the train-pipe pressure existing in a passage 3, and at the other side to that existing in the valve chamber 5 and a pressure chamber 6 ; a supply valve 16 and release valve 18 for the service brake cylinder operated by differential pistons 14, 31, the space 13 to the left of the piston 14 communicating by passages 12, 72 with an application chamber 71 ; an emergency or by-pass valve 33 operated by differential pistons 40, 41; and a local-venting valve 46, 51. The service auxiliary reservoir and brake cylinder are connected to passages 61, 24 which are open to the valve chambers 17, 19 respectively, and the emergency reservoir and brake cylinder are respectively connected to passages 37, 43 which communicate with the valve chamber 36. In release position, Fig. 2, the valve chamber 5 and pressure chamber 6 are charged throug feedgrooves 55 and through a check valve 53 and passages 56, 57, 58 ; the service reservoir is charged through passages 60, 59, 61 ; the emergency reservoir through passages 62, 63, 37 ; and the valve chamber 47 through passages 64, 48, and 50. The service brake cylinder is vented through passages 24, 28, 29, 30, the emergency brake cylinder through passages 43, 79, 80, and the application chamber 71 through passages 72, 65, 66, 67, 69. In a service application, Fig. 3, the piston 4 moves so as to uncover a port 70, through which and passages 12, 72 the chambers 13, 71 are charged, whereupon the piston 14 is operated to cut off the exhaust ports 28, 29 and to open the chamber 17 to the service brake cylinder through ports 23, 24. The space between the pistons 14, 31 is also open to the service brake cylinder by passages 32, 34, 35, 24, so that when the brake - cylinder pressure becomes proportional to that in the application chamber, the piston 14 returns to shut off further supply. Moreover, any leakage from the brake cylinder is automatically made up by movement of the piston 14 towards the reduced brake - cylinder pressure. In emergency applications, Fig. 4, the piston 4 moves to its extreme position, whereupon the space to the right of the piston 41 is exhausted through passages 74, 68, 69 and the space to the left of the piston 40 is charged through ports 70, 76, 75, so that the valve 33 is operated as shown. The application chamber 71 is then charged from the emergency reservoir through passages 37,77,78 as well as from the pressure chamber through ports 12, 72, so that the piston 14 is operated as before. The space to the right of the piston 14 is, however, then open to atmosphere through passages 32, 79, 80, so that the piston 14 is maintained in application position and the service brake cylinder is charged from the service reservoir until the pressures fully equalize. The emergency reservoir is vented into the emergency brake cylinder through passages 37, 43, and may also be vented into the service brake cylinder by ports 42, 35, 24. Moreover, the local-venting valve 51 is raised to vent the train-pipe through passages 52, 54 and check valve 53, since the lower side of the piston 46 is subjected to pressure from the emergency reservoir by ports 37, 63, 88, 50, while the upper side is vented into a reduction reservoir 85 by passages 48, 86, 84, 82, 83. In order to prevent the piston 4 from moving to emergency position when, during service applications, the train-pipe pressure becomes reduced by leakage or by a further venting, the main valve 10 is constructed so that, when moved slightly beyond the service position, Fig. 3, the valve chamber 5 is vented to the reduction chamber by ports 70, 76, 84, 82, 83. In order, however, to ensure that the piston 4 shall move to its extreme position, Fig. 4, when an emergency application is desired, a port 88 in the main valve is arranged to connect the valve chamber 5 to the emergency reservoir by passages 63, 37, as shown in Fig. 4. For a given reduction of trainpipe pressure, the apparatus described gives a greater brake-cylinder pressure than is obtained with the ordinary standard apparatus, and in order to compensate for this so as to obtain uniform braking throughout a train having some cars provided with the apparatus described and others with standard apparatus, a cavity 93, Fig. 2, is formed in the main valve 10 so that, as the valve moves from release position during an application, the application chamber 71 is connected to the reduction chamber 85 by ports 72, 93, 87, 82, 83, this connexion being cut off as soon as the piston 14 is operated. Graduated release of the brakes after service applications may be obtained by gradual increase in train-pipe pressure, whereby the piston 4 is returned to release position, and the application chamber and service brake cylinder are vented. In the release position of the main valve 10, however, the emergency reservoir communicates with the valve chamber 5 so as to return the piston 4 and prevent full release. Figs. 12 and 13 show the preferred arrangement of the various parts of the valve device in an actual construction, the several valve mechanisms being made as separate units.